package com.tantinevincent.vector;

/**
 * Interface of vector, 
 * define get vector's length, vector's indices( all index in array) and value method. 
 * @author Vincent
 *
 */
public interface IVector {
	/**
	 * Get length of vector( not equals length of indices ).
	 * @return the length of vector.
	 */
	public int length();
	/**
	 * Get all index in vector, it's a sorted integer array.
	 * @return the indices of vector.
	 */
	public int[] getIndices();
	/**
	 * 
	 * @param index the index of vector, the index should be smaller than length, and bigger than -1. 
	 * @return the value of vector.
	 */
	public double get(int index);
}
